WO2001051211A2

WO2001051211A2 - Hammer mill rotor

Info

Publication number: WO2001051211A2
Application number: PCT/DK2001/000029
Authority: WO
Inventors: Henning JØRGENSEN
Original assignee: Sprout-Matador A/S
Priority date: 2000-01-14
Filing date: 2001-01-15
Publication date: 2001-07-19
Also published as: AU2664501A; WO2001051211A3

Abstract

For the grinding of grain in the agricultural sector it is known to use hammer mills with a hammer carrying rotor construction made as a row of shaft mounted discs, which are kept interspaced by means of smaller shims in such a manner that the interspaces can accommodate outwardly projecting hammers cooperating with a surrounding mill screen being pivotally held on shaft elements extending between the shims near the peripheries thereof. In connection with the invention the spacer shims are changed into ordinary, hammer carrying discs which are only provided with local recesses (6) for receiving the inner ends of the hammers (10), while in places angularly offset from these recesses they carry shafts for hammers mounted outside of each of the adjacent discs, which are at these places provided with corresponding recesses. Accordingly it is possible to provide such a rotor with simple, axially closely juxtaposed hammers all over the length of the rotor, whereby a high efficiency of the mill is achievable.

Description

Hammer mill rotor

The invention relates to a rotor construction for hammer mills . Configuration in normal practice is that the rotor is built up of circular plates with distance between the plates brought about by shims of different thickness determined by the hammer thickness. This provides a rotor with two or more hammers placed in the same circular path, and herewith only narrow cylindrical bands on the sieve are swept.

A second construction provides the possibility for axial displacement of the hammers by means of bushes which are mounted when the mill rotor is assembled. This system is difficult to mount and consists of many parts. With a third known construction, there is an increased distance between the circular plates. The distance between the plates provides the possibility for the mounting of, e.g., rectangular, tubular items with displaced slots in which the hammers are placed, which means that the whole area of the sieve is swept. The disadvantage of this system is that the tubular items, which are mounted by means of bolts, get worn, and due to the great centrifugal forces can hereby cause great damage if they fall off, or they can give rise to great imbalances. The rotor according to the present invention is characterised in that the circular plates are arranged without any distance, or with only very small distance, between them, and that although the hammers are still mounted projecting from the spaces between two plates, this is effected in such a manner that inwardly they are accommodated in a recess in the intermediate plate, which in itself constitutes the one part of the two plates which form the suspension for adjacent hammers. In other words, a set of hammers will appear opposite all of the plates, namely pivotaUy suspended in between the individual plate's adjacent plates and completely without connection with that plate in whose plane the individual hammers are projecting.

This construction principle is illustrated by way of ex- ample in fig. 1, which is an exploded view of a section of a drum rotor according to the invention. A number of drum- forming disks 2 and 4 are arranged in tight formation on a not-shown drum axle, and each disk is configured with two cut-outs 6 opposite each other and, displaced at 90° from the cut-outs, two holes 8 opposite each other near the periphery of the disk. For each of the cut-outs there is a related hammer 10, which is merely not connected with the associated disk.

As will be seen in the figure, the successive disks 2 and 4 are turned 90° in relation to each other, so that the cutouts 6 lie on a horizontal diameter of the disks 2 but on a vertical diameter of the disks 4. When the disks are brought closely together, the hammers 10, each of which has a hole 12 at its inner end, are mounted by anchoring rods being in- serted through the holes 8, which is indicated by stippled lines 14. With this insertion, the ends of the rods will pass alternately through a hole 8 and a cut-out 6, and with each passage of a cut-out, a hammer can be hooked in on each of the relevant rods, so that the individual hammers are sus- pended firmly and pivotally on relatively short rod sections between the holes 8 in the two relevant adjacent plates 2.

In itself, this does not involve any great changes in relation to the known technique, but the essential change consists in that a disk now lies in each "hammer plane", and which in itself can constitute a "host disk" for each set of hammers, so that the number of hammers can be doubled for an appreciable increase in the capacity of- the hammer mill.

It will be understood that with uniform rotational distribution, work can be effected with a greater or a smaller number of hammers/cut-outs per disk, e.g. 2-8. A certain imbalance can possibly be accepted for the one set of disks 2, if this is counterbalanced by a corresponding imbalance for the second set of disks 4. Fig. 2 shows an example with four hammers per disk.

Despite the existence of the cut-outs 6, the peripheries of the disks will, however, predominantly give the assembled drum the character of a "whole drum", i.e. there will not be any appreciable space in which the filled-in and more or less milled corn can conceal itself during operation. This will contribute towards an increased capacity of the mill, since it will generally lead to an increased concentration of grinding material in the cylindrical space between the rotor drum and the surrounding sieve structure. It has been ascer- tained that the construction also results in a reduced power consumption.

The construction according to the invention will not exclude that use can still be made of what is in itself a known principle with regard to a desirable lengthways turning of the hammers after these have become worn round at their outer ends. It is obvious that in the dismounting and remounting of the said anchor rods, the opportunity will be provided of remounting the hammers individually in their lengthways turned position, in which case the hammers will also be provided in advance with holes 12' at their outer ends. This procedure can be eased considerably merely by configuring the active support disks with extra holes 8', which will thus appear at a distance from the holes 8 which corresponds to the distance between the holes 12 and 12' in the hammers, namely such that when turned around their holding rods 14, the hammers can be brought into a position in which their outer ends can be caught by a new anchor rod 14' inserted through the holes 8' and 12' .Hereafter, the hammers can be released by the withdrawal of the original anchor rods 14, after which they will automatically be operational by being able to swing out in the lengthways-turned position by swinging out from the new anchor rods 14' .

This procedure is illustrated in fig. 3 by the sequence I-II-III, and it will be seen that there will be room for such a turning merely providing that the cut-out 6 is sufficiently broad.

Traditionally, the plates 2 will consist of steel, but with the current compact construction of the rotor this will hereby be relatively heavy. The weight can be reduced by configuring the plates with various cut-outs, e.g. as shown at 16 in fig. 2, but the invention will also comprise the modification that a part number of the plates are configured in lighter materials such as a suitable composite material. Moreover, there will be nothing to prevent that several adjacent plates can appear as a block unit in which cut-outs 6 are provided by milling out at the relevant places.

Claims

C L A I M S:

1. Rotor construction for hammer mills, consisting of a series of axle-mounted disks, which between them support outer rotation axles for the retention of respective, projecting hammer elements in a manner in which these can swing, in that between the disks there are mounted suitable, distance-providing intermediate disks, c h a r a c t e r i s e d in that the rotor is consistently built up with the said axle-mounted disks in such a manner that these disks without any distance, or with only very small mutual distance between them, each form intermediate disks for two hammer axle-supporting disks, while they themselves are not only configured with recesses for the accommodation of the relevant hammers, but are also hammer axle-supporting for hammers disposed opposite the adjacent disks, in that the disks are alternately displaced at an angle from each other so that the recesses in each disk are fully covered at the sides by the adjacent disks .

2. Rotor construction according to claim 1, which comprises disks of steel, c h a r a c t e r i s e d in that a part number of the disks are configured in a lighter material such as a suitable composite material.